1. Field of the Invention
The present invention relates to an apparatus and method for sensing vibrations of a washing machine and, more particularly, to an apparatus and method for sensing vibrations of a washing machine capable of controlling a washing machine based on the actual amount of vibrations generated from the washing machine.
2. Description of the Related Art
In general, a washing machine removes a contaminant from the laundry soaked in a washing solution by applying a proper frictional abrasion or applying a mechanical action such as vibrations to the laundry.
In washing the laundry, the washing machine performs a washing process in which a mechanical force is applied to the laundry mixed in the washing solution, a rinsing process in which the washing solution with contaminant is removed from the laundry, and a dewatering process in which rinse water is removed from the laundry.
The structure and operation of a general drum washing machine will now be described with reference to the accompanying drawings.
FIG. 1 is a front view schematically showing the related art drum washing machine.
As shown in FIG. 1, the related art washing machine includes a housing 10 that supports the configuration of a main body and having a certain space therein; an outer tub 20 installed within the housing 10; an inner tub 30 installed within the outer tub 20 and in which a washing operation is performed; a motor (not shown) installed on a lower surface of the outer tub 20 and driving the inner tub 30; a damper 50 installed at a lower portion of the outer tub 20 and damping vibration which is generated from the outer tub 20 and the inner tub 30 and transferred to the housing 10; and springs 60 installed at upper portions of the outer tub 20.
In the drum washing machine, water is supplied in washing and rinsing laundry, and when water is filled up to a proper water level, water supply is stopped and the motor is driven. Then, the inner tub 30 is repeatedly rotated clockwise and counterclockwise.
In dewatering, the water within the inner tub 30 is drained out, the inner tub 30 is rotated clockwise and counterclockwise at a lower speed by the motor to perform a certain even laundry distribution and then accelerated to perform a regular dewatering stroke.
When the laundry is not evenly distributed within the washing machine so laundry unbalancing or abnormal vibrations occur, severe vibration and noise are generated in the dewatering process.
In order to solve the problem, the related art washing machine calculates an unbalance mass by using variation of an RPM (Revolution Per Minute) during a dewatering stroke and controls the washing machine upon determining whether or not there is an abnormal vibration based on the calculated value.
When an initial unbalance mass is sensed to be high, the rotation is stopped and laundry distribution starts. Also, when the unbalance mass is more than a reference value during the accelerated operation, the rotation is stopped and the laundry distribution is executed again.
However, in the related art washing machine, because the amount of vibrations is not directly measured but abnormal vibrations are sensed by calculating the unbalance mass, a problem arises in that an abnormal vibration may be generated with respect to loads whose unbalance mass is hardly sensed, so the washing machine walks or its inner tub severely collides with the outer tub.